Stock driveshaft with a TH400?

[TwoLaneBlackTop]

I have a short tail-shaft BOP pattern TH-400, I know I must change the yoke to a TH400 type but will the driveshaft it self need to be shortened?

If so, how much and what length yoke should I use.

If not what is the proper yoke dimensions for the stock length driveshaft.

Any help is vastly appericated.